1. Field of the Invention
The present invention relates to Cu-based bulk amorphous matrix composite materials and a production method thereof, and more particularly to Cu-based bulk amorphous matrix composite materials containing high fusion point elements, which considerably increase the elongation rate while minimizing the reduction of strength of the bulk amorphous materials through adding high fusion point elements, Ta and/or W, so as to control abrupt fracture behaviors of the amorphous materials, and to a production method thereof.
That is to say, the present invention relates to Cu-based bulk amorphous matrix composite materials containing high fusion point elements, in which a certain ratio of Ta or W solid solution is dispersed in a Cu-based matrix with above 90% of amorphous volumetric ratio, providing excellent mechanical properties such as strength, elongation rate and so forth, and to a production method thereof.
2. Description of the Prior Art
Recently, as in pursuing of scale-down, lightening and multifunctioning of machine parts, it has been requiring a multi functional structural metallic materials improving mechanical properties and functionibility two or more times over the existing structural materials. Bulk type amorphous metallic materials are the innovative materials to satisfy such requirements of times, so that they have been world widely studying actively. Bulk type amorphous materials in which their atomic structures becomes to be amorphous are regarded as the next-generation structural metallic materials exceeding limits of physical properties of the existing metallic materials and are estimated as strategic metallic materials the new industry of the future requires after they had been initially reported by Caltech of USA in 1993.
Among amorphous materials, zirconium-based alloy has been commercially developing as materials for sporting goods and the military. However, since the element, zirconium has a specialty in light of resources, it has been now developing various kinds of commercial alloy amorphous materials. Representative one of the commercial metallic materials, Cu-based amorphous materials have characteristics similar to the other alloy system and have a high value in economic aspects as well.
Johnson et al., USA, reported Cu-based amorphous alloy containing about 40˜60 atomic weight %, and registered Patent claiming compositions including the above composition. (Refer to a document, JOURNAL OF APPLIED PHYSICS, VOL. 83, 1998, p7993, Johnson et al., WO96/24702 A1, 1996). Also, Inoue, Japanese, registered Patent claiming compositions including 40˜70 atomic weight % of Cu (Inoue et al., WO02/053791 A1, 2002, Japanese Patent Application No. 2002-256401).
However, although bulk type amorphous materials (or bulk type nano composite materials) developed by present have strength and elastic limit higher than 2˜4 times in comparing with the existing metallic materials, it is difficult for them to be applied to structural materials because of their abrupt fracture behaviors. Such brittleness is caused by a formation of shear bands so that it must be resolved to put them to practical use.
Typically, in order to increase toughness of materials with brittleness such as ceramics, it has been using a method for dispersing ceramic particles or ductile metallic crystalloid. Such method, however, causes a fracture phenomenon such as a crack deflection, a branching, plural shear bands, blunting and so forth during cracking.
Accordingly, the method can be adapted to bulk type amorphous materials having the similar mechanical properties to those of ceramic materials.